Well, whether Mulatto, Octaroon, Quadroon, or Griffe..we know African blood was there or thought to be there..or known to be there regardless of whether it showed in the person's appearance..That is, there could be a very white looking mixed African and white and to be called Mulatto or whatever could be because the ancestry was known by the census taker..
No Indian and white mix person looks at all as though there is African blood there..so I really don't believe any person who was only Indian and white ever got called Mulatto by anyone..But I do believe that many who were Indian, African AND white did get called Mulatto for the Black and white part, and the Indian part was just ignored, if it was known about by the census taker..